Chapter 15: special senses receptors, Olfaction, Gustation

General Senses

temperature, pain, touch, pressure, vibration, proprioception

- receptors in body wall and receptors in walls of viscera

Special senses

- gustation(taste), olfaction (smell), vision, hearing, equilibrium (vestibular sensation )

- receptors in head

Special senses receptors

- specialized cells ( except smell)

- F: dectection and transduction( conversion of signal to electrical signal/ AP

General senses receptors

- receptor at end of sensory neuron( a cranial or spinal nerve)

receptor types

-Chemoreceptors (chemicals)

-mechanoreceptors (mechanical touch pressure)

- photoreceptors (light)

Smell

-receptor cell : olfactory neurons

-receptor: chemorecpetor (air)

-Integration: temporal lobe

Taste

-receptor cell: gustatory cells

- receptor: chemoreceptor( salvia)

- pathway: brainstem, thalamus

Integration: parietal lobe

Vision

-receptor cell: rods and cones

-receptor: photoreceptor

- pathway: thalamus

- integration : occipital lobe

Hearing

- receptor cell: hair cells in cochlea

- receptor: mechanoreceptor

- pathway: brainstem, thalamus

-integration : temporal lobe

Vestibular sensation

- receptor cell: hair cells in vestibule

- receptor: mechanoreceptor

- pathway: brainstem, thalamus

Integration : parietal lobe

tastebuds

Located on rounded projections on tongue, contains gustatory and other cells

gustatory cell

- receptor

- detected chemicals dissolved in salvia in taste buds

Senstaion of taste

chemical stimulus

step 1: sensation of taste

1: receptor responds to detects specific stimulus

step 2: sensation of taste

2: chemical is dissolved in salvia, detected by receptor

step 3: sensation of taste

3: molecule movement depolarizes gustatory cell

step 4: sensation of taste

4: neurotransmitter released

step 5: sensation of taste

5: AP in cranial nerve to brain and cortex

Sweet taste

glucose and fructose

salty

Na+ ions

Sour

H+ ions

Bitter

N. Containing compound: alkaloids, posions + more

Umami

amino acids, glutamate

olfactory epithelium

lining in superior region of each nasal cavity

olfactory neuron

- receptor

- F: detect odorant , carry signals from nasal cavity to olfactory bulb

olfactory cilia

- end of dendrites of olfactory neuron, extend into roff of nasal cavity

-F: detect odorants

Olfactory bulb

- region where olfactory neuron and olfactory tract synapse

olfactory tract

- axons olfactory bulb neuron

- F: carries signal to brain

Step 1: sensatsion of smell

1: odorant detected by olfactory cilia

step 2: sensation of smell

2: depolarizion of olfactory neuron (AP)

step 3: sensation of smell

3: AP transmitted to olfactory bulb and tract

step 4: sensation of smell

4: Ap to brain cortex